A script kiddie(also known as skid, skiddie, script bunny etc) is a unskilled person who uses scripts or programs to attack networks, systems and such. this term widely used among hackers to describe a newbie who is new to hacking and uses tools, or to describe kids who DDoS video game players or deface websites with ready made tools and scripts.
according to a Carnegie Mellon report prepared for the U.S. Department of Defense in 2005, script kiddies are defined as:
“The more immature but unfortunately often just as dangerous exploiter of security lapses on the Internet. The typical script kiddy uses existing and frequently well known and easy-to-find techniques and programs or scripts to search for and exploit weaknesses in other computers on the Internet--often randomly and with little regard or perhaps even understanding of the potentially harmful consequences”
Script kiddies use many programs, scripts and tools which are easy to find such as RATs, havij, SQLmap, metasploit framwork etc
to attack systems. A ‘skid’ is sometimes used to describe a person who writes poor/messy code or uses code that other people wrote.